基于单向拉伸的7A09铝合金本构方程  

Constitutive equation of 7A09 aluminum alloy based on uniaxial tension

作　　者：马康 宋健 冯瑶 袁斌先[2] Ma Kang;Song Jian;Feng Yao;Yuan Binxian(Tianjin Long March Launch Vehicle Manufacturing Co.,Ltd.,Tianjin 300462,China;School of Mechanical Engineering,Tianjin University of Technology and Education,Tianjin 300222,China)

机构地区：[1]天津航天长征火箭制造有限公司,天津300462 [2]天津职业技术师范大学机械工程学院,天津300222

出　　处：《锻压技术》2023年第4期249-255,共7页Forging & Stamping Technology

基　　金：天津市教委科研计划项目(2020KJ106)。

摘　　要：通过不同温度及应变速率下的单向拉伸试验,获得了7A09铝合金板材关键力学性能参数的变化规律。结果表明:在应变速率一定的条件下,当温度降低时,7A09铝合金的抗拉强度与流动应力随之升高,当温度升高时,断后伸长率有明显提高。基于Fields&Backofen本构方程,建立7A09铝合金温拉伸时的应力-应变本构模型,分析和探讨了在不同温度状态下7A09铝合金的强化规律。结果表明:7A09铝合金的应变强化指数随着温度的升高而减小,而应变速率敏感性指数则显著提高,应变速率的强化作用得到了显著增强。以温成形技术生产的桁条加强件为例,利用本构模型进行有限元模拟,确定成形速度为5000 mm·s^(-1)时,零件减薄率最小;温度为175℃时,零件壁厚分布最为均匀,最小减薄率仅为3.8%。The variation rules of key mechanical property parameters of 7A09 aluminum alloy sheet were obtained by uniaxial tensile tests at different temperatures and strain rates.The results show that under the condition of constant strain rate,the tensile strength and flow stress of 7A09 aluminum alloy increase with the decreasing of temperature,and the elongation after fracture increases obviously with the increasing of temperature.Based on the Fields&Backofen constitutive equation,the stress-strain constitutive model of 7A09 aluminum alloy during warm tension was established,and the strengthening rules of 7A09 aluminum alloy under different temperature conditions were analyzed and discussed.The results show that the strain hardening index of 7A09 aluminum alloy decreases with the increasing of temperature,while the strain rate sensitivity coefficient increases significantly,and the hardening effect of strain rate is significantly enhanced.For the stringer reinforcement by warm forming technology,the finite element simulation was carried out by using the constitutive model,and it is determined that the thinning rate of parts is the minimum when the forming speed is 5000 mm·s^(-1).When the forming temperature is 175℃,the wall thickness distribution of parts is the most uniform,and the minimum thinning rate is only 3.8%.

关 键 词：7A09铝合金 温成形 单向拉伸 本构模型 应变速率 

分 类 号：TG146.5[一般工业技术—材料科学与工程]